奥氏体高锰钢的切削过程与形变强化规律

Cutting processes and deformation hardening behavior of austenitic high-manganese steel

金属切削过程是切削层金属的塑性变形和断裂过程 .切削过程中 ,金属的形变强化、裂纹形成与长大的知识对理解切屑分离和流出是必要的 .本文应用快速落刀及金相分析方法研究了奥氏体温锰钢 5 0Mn18Cr4切削变形过程中的形变强化和微裂纹形成与扩展规律 .研究表明 ,切削过程中的形变强化规律符合幂函数规律 ;切削刃处切削材料的分离是该局部材料形变强化达到断裂应力的结果 ;奥氏体高锰钢切屑属挤裂型切屑 ;切屑断裂源于剪切带 ;在切屑沿前刀面流出过程中 。

Metal cutting is the process of plastic deformation and fracture. Information about strain hardening of meterials, microcrack formation and growth in the cutting process is necessary to understanding the chip dechesion and flow out of the material at the cutting lip. Deformation hardening and fracture behavior of austenitic high-manganese steel 50Mn18Cr4 in the cutting processes has been studied by means of impact-falling cutter and microscopic examination in this paper. The results indicate that the deformation hardening can be described by a power function and that the difference in flow speed of chip along the tool face results in the flex, which tends to blockade the flow nearest tool face. The shear instability forming shear band occurs since the interreaction of the flex with the chip flow nearest tool face. Microvoid formation, growth and coalescence in the shear band results in the chip of tear type.